Molar Incisor Hypomineralization of Eight- and 14-year-old Children: Prevalence, Severity, and Defect Characteristics.

Purpose: To report on the prevalence, severity, defect location, and other characteristics of molar incisor hypomineralization (MIH).

Methods: Representative samples of eight- and 14-year-old children (1,179 and 1,156, respectively) in three Greek cities were examined for MIH in the classroom using European Academy of Pediatric Dentistry criteria. MIH either mild or severe included the recording of defect color and location.

Results: MIH prevalence was 21 percent (498 of 2,335 children), with a statistically significant difference in one city (16 percent) from the other two (23 percent, P=.007; and 23 percent, P=.002). In 46 percent of MIH cases, only permanent first molars (PFMs) were affected. MIH severity was associated with age (severe MIH eight-year-olds comprised 13 percent; 14-year-olds comprised 35 percent, P<.001) and with number of affected teeth per child (mild equals 2.44, severe equals 4.22, P<.001). The lingual surfaces of mandibular PFMs and palatal/lingual surfaces of all incisors were significantly less frequently affected (all less than 10 percent) than their buccal/labial counterparts (P<.0001).

Conclusions: Predominantly mild MIH was common in children's permanent teeth, with some intracountry variation. A surface predilection of MIH opacities was clearly revealed. The severity in 14-year-olds was threefold that of eight-year-olds.